Remove "Yes"/"No" and use "true"/"false" consistently in `docker info`

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
(cherry picked from commit c6b7bd1aa6b94ab242d6310419f1c3a7964ffa02)
Signed-off-by: Tibor Vass <tibor@docker.com>

api/client/info.go

@@ -74,13 +74,11 @@ func (cli *DockerCli) CmdInfo(args ...string) error {
 		if info.Swarm.Error != "" {
 			fmt.Fprintf(cli.out, " Error: %v\n", info.Swarm.Error)
 		}
+		fmt.Fprintf(cli.out, " IsManager: %v\n", info.Swarm.ControlAvailable)
 		if info.Swarm.ControlAvailable {
-			fmt.Fprintf(cli.out, " IsManager: Yes\n")
 			fmt.Fprintf(cli.out, " Managers: %d\n", info.Swarm.Managers)
 			fmt.Fprintf(cli.out, " Nodes: %d\n", info.Swarm.Nodes)
 			ioutils.FprintfIfNotEmpty(cli.out, " CACertHash: %s\n", info.Swarm.CACertHash)
-		} else {
-			fmt.Fprintf(cli.out, " IsManager: No\n")
 		}
 	}